This invention is related to small mirrors such as dental mirror instruments and particularly to a mirror with a protective mask having an integral removal tab for use with such instruments.
Dentists have long used small, handheld mirrors when performing dental procedures such as oral surgery and restorative dentistry. The stereotypical dental mirror has a stainless handle with a reflecting surface affixed at an angle on the end of the handle. The reflecting surface in such a dental mirror is usually provided by a conventional glass mirror.
Such dental mirrors have disadvantages. They are costly to manufacture. They have a high tendency to fog up due to the relatively large heat capacity and conductance of the glass and metal materials. This type of dental mirror also requires sterilization between patients via chemical or thermal processes.
Although the material in these dental mirrors can withstand chemical and thermal sterilization, sterilizing these mirrors has several drawbacks. The interface between the glass reflective surface and the metal handle is susceptible to retaining germs which may occasionally survive the sterilization process. Even when sterilization of the mirror is successful, unsightly debris and grit may be trapped in the gap around the glass mirror and can be difficult to remove. The sterilization process is an added expense, and the glass mirror tends to develop scratches and blotches from use and sterilization.
The cost of dental mirrors becomes an important factor with a new dental technique called air abrasive dentistry. In this procedure, the dental drill normally used to remove decayed tooth material is supplemented or replaced by a high velocity air stream containing particles which abrade away the decayed tooth portions. In such procedures, an inherent problem is that some of the abrasive particles will ricochet off the tooth and impact the mirror surface with sufficient velocity to etch and damage it. Dental mirrors used in such procedures can have a very short lifetime, depending on the location of the cavity, and can become unusable within a few seconds.
For these and other reasons, disposable dental mirrors have become popular in recent years. Disposable dental mirrors may be discarded after use so sterilization is not needed and transmission of viable pathogens between patients is completely avoided. In order to be economically viable, a disposable dental mirror must be very inexpensive to manufacture and distribute. In pursuit of this goal, disposable dental mirrors have been developed that use thin, plastic, reflecting films in place of conventional rigid plastic or glass mirrors. See for example, U.S. Pat. No. 6,142,777 and U.S. patent application Ser. No. 09/633,903, assigned to the assignee of the present application.
It is important to protect the mirror surface during manufacturing and shipping. This is especially true for disposable mirrors, which are frequently packaged with a number of mirrors loaded loosely into a box or other container, and also for mirrors which have a reflecting surface made of a metallized, plastic film, whose surface is more delicate than that of glass mirrors.
One well-known method of providing protection is to apply a protective layer or mask of plastic, foil, or other material over the mirror surface. This mask is then removed by a dentist prior to use. However, this also requires provision of some method of quickly and easily removing the mask.
While masks can be removed without the provision of a removing means, this can be awkward and difficult to do. The difficulty is increased if a dentist is wearing protective gloves. Additionally, with thin film reflective surfaces, there is an increased chance of damaging the surface if no means for removing the mask is supplied.
One common mechanism for removing a mask is the provision of a separate tab attached to the top of the mask and which is used to remove the mask. Disadvantages of this method include the cost of extra steps required to attach the tab, a tendency to attract debris by the adhesive used to attach the tab, and the fact that it is not uncommon for a small percentage of such tabs to come loose and fail.
Another method for providing a means for removal is to fold the mask back on itself so that a piece of the mask material protrudes from the surface of the mirror where it can be grasped. While this method reduces the problems of failed tabs and or debris sticking to the tab, it requires more expensive machinery to carry out.
The present invention includes a new system for providing a dental mirror with a reflecting surface comprising a metallized film or other reflecting material covered by a protective mask with an integral removal tab that may be quickly and easily applied to a dental mirror handle and mirror substrate by automatic machinery.
In this system, mirror assemblies are cut from a multi-layer laminate which includes a release layer on the bottom which is adhesively attached to a thin, reflecting film, which is in turn attached to a protective mask layer. Individual mirror/mask assemblies are die cut from the multi-layer assembly by a cutting process that creates a shaped reflecting surface covered by a protective mask that is congruent with the reflecting surface except for the addition of one or more small tabs projecting beyond the reflecting surface which are part of the protective mask and by which the protective mask may be easily removed.
The advantages and operation of the present invention are more fully set forth in the following description of the preferred embodiment and by reference to the drawings, of which:
FIGS. 1A through 1D show prior art removal tabs;
FIGS. 2A and 2B are top and front views respectively of a dental mirror having a protective mask with an integral tab in accordance with the present invention;
FIG. 3 shows a multi-layer lamination that may be used to make the mirror and mask shown in FIGS. 2;
FIG. 4 is a top view showing cuts made in the laminate of
FIG. 3 to create mirror/mask assemblies;
FIG. 5 illustrates how multiple mirror/mask assemblies may be formed on a roll of laminate for automatic placement on a dental mirror instrument head;
FIG. 6 is a sectional view along the section line indicated in FIG. 4 illustrating the cuts made through the various layers of the lamination of FIG. 3 in forming the mirror/mask assembly; and
FIGS. 7 and 8 show first and second cutting steps for one preferred method of creating the mirror/mask assemblies of the present invention.